I agree with others on here; there is way too much intensity in the TR plans. Some people seem to be able to complete a few blocks of it, but not consistently, and not year after year.
Just because someone can complete a block that is chock-full of intensity doesn’t mean it’s the best way to get faster!
As others have said, working out what’s right for you is the hard part, and its individual for sure. I keep a decent training diary, and this helps me work out what weekly TSS I can hold sustainably (and I can see how much comes from intensity and how much from duration, roughly).
Looking at your training diary can also help you see how many hard workouts a week you can tolerate, and sometimes what the cost of that is. I can see that I’ve done three hard workouts for a few blocks back-to-back, but looking closer I can see that I had to trim my endurance rides due to fatigue.
What works for me is two intense sessions (and I make these good), one long ride and the rest easy. I am making steady progress, so there’s clearly enough stress/recovery to trigger adaption. This part is key; to be honest with yourself you have to test, train, test to make sure that – over time – you’re making progress. If you are doing this consistently, you’ve probably got the intensity/recovery balance about right.